4isq
Binding domain of Botulinum neurotoxin DC in complex with human synaptotagmin IBinding domain of Botulinum neurotoxin DC in complex with human synaptotagmin I
Structural highlights
Function[SYT1_HUMAN] May have a regulatory role in the membrane interactions during trafficking of synaptic vesicles at the active zone of the synapse. It binds acidic phospholipids with a specificity that requires the presence of both an acidic head group and a diacyl backbone. A Ca(2+)-dependent interaction between synaptotagmin and putative receptors for activated protein kinase C has also been reported. It can bind to at least three additional proteins in a Ca(2+)-independent manner; these are neurexins, syntaxin and AP2. Publication Abstract from PubMedBotulinum neurotoxins (BoNTs) can cause paralysis at exceptionally low concentrations and include seven serotypes (BoNT/A-G). The chimeric BoNT/DC toxin has a receptor binding domain similar to the same region in BoNT/C. However, BoNT/DC does not share protein receptor with BoNT/C. Instead, it shares synaptotagmin (Syt) I and II as receptors with BoNT/B, despite their low sequence similarity. Here, we present the crystal structures of the binding domain of BoNT/DC in complex with the recognition domains of its protein receptors, Syt-I and Syt-II. The structures reveal that BoNT/DC possesses a Syt binding site, distinct from the established Syt-II binding site in BoNT/B. Structure-based mutagenesis further shows that hydrophobic interactions play a key role in Syt binding. The structures suggest that the BoNT/DC ganglioside binding sites are independent of the protein receptor binding site. Our results reveal the remarkable versatility in the receptor recognition of the BoNTs. Crystal Structures of Botulinum Neurotoxin DC in Complex with Its Protein Receptors Synaptotagmin I and II.,Berntsson RP, Peng L, Svensson LM, Dong M, Stenmark P Structure. 2013 Sep 3;21(9):1602-11. doi: 10.1016/j.str.2013.06.026. Epub 2013, Aug 8. PMID:23932591[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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